Multiple hearth incinerator



5 Sheets-Sheet l ATTORNEY June 14, 1955 H. J. HARTLEY MULTIPLE HEARTH INCINERATOR .Y o a a o Q a i n 5 R 0 v .H 6 J Q 0 B 0 F y T m o o i i H i Flled Nov 12. 1949 wqwqi $6 2 Q3 E v June 14, 1955 H. J. HARTLEY 2,710,585

MULTIPLE HEARTH INCINERATOR Filed NOV. 12, 1949 5 Sheets-Sheet 2 FIG. 2. 5&

an: 0 y i 56' t a a 9 '5 1 /*/0 55 4 l I s l INVENTOR. HENRY J. HARTLEY BY fl' F/G.8. g

AT TOR/VQK June 14, 1955 H. HARTLEY 2,710,585

MULTIPLE mm mcmsauoa Filed Nov. 12, 1949 5 Sheets-Sheet 3 IN V EN TOR.

I12 HENRY J. HARTLEY ATLQRNEY H. J. HARTLEY MULTIPLE HEARTH INCINERATOR June 14, 1955 5 Sheets-Sheet 4 Filed Nov. 12, 1949 ATTORNEYw 5 Sheets-Sheet 5 H. J. HARTLEY MULTIPLE X-IEARTH INCINERATOR June 14, 1955 Filed Nov.

INVENTOR. HENRY J. HARTLEY ATTORNEY United States Patent 0 MULTIPLE HEARTH INCINERATOR Henry J. Hartley, Los Angeles, Calif., assignor to Pacific Foundry Company, Ltd., San Francisco, Calif a corporation of California Application November 12, 1949, Serial No. 126,813

5 Claims. (Cl. 110-8) This invention is concerned with furnaces, particularly those of the multiple hearth type, and provides improvements in furnace apparatus. The invention is particularly adapted to the incineration of garbage and like materials which are markedly heterogeneous both with respect to particle size and substance, but is of general utility and may be employed in the burning, roasting, drying and other heat treatment of a variety of materials including ores, concentrates, precipitates, sludges and slurries.

Garbage incineration, particularly when it is conducted on a large scale, presents a number of serious problems. The moisture content of garbage is usually high and extremely variable from batch to batch and even within the same batch. Moreover, there is a wide variation in the size and composition of the objects and materials in the garbage. All of these factors tend to produce wide variations in the degree of combustibility. Since sorting, except to a limited extent, is impractical, garbage usually is burned in an unsorted condition, frequently by firing against the mass thereof, and because of the varying degree of combustibility there is a marked tendency to produce smoke, fumes and foul odors during burning. Moreover, large objects (such as animal carcasses) in the garbage tend to clog conventional incinerator equipment and may require frequent shut downs for cleaning and repair.

I have discovered that the foregoing difiiculties can be avoided, or at least greatly diminished, by burning the garbage on a plurality of superposed sectional collapsible hearths separated from each other by combustion chambers, each of which is separately fired. As each hearth is collapsed the garbage retained on a hearth section is tumbled downward through the flames in a combustion chamber onto the hearth immediately below, where it continues to burn until that hearth is collapsed.

At that time the garbage is again tumbled through the flame of a combustion chamber to the next lower hearth, this operation being repeated until combustion of the garbage is substantially complete. Preferably the garbage is tumbled from hearth to hearth in such quantitles and at such intervals that the combustion chambers do not become choked and the firing takes place at a level above the pile on any given hearth. The tumbling aids combustion and by keeping the firing at a level above the pile on a hearth, firing against the mass is avoided. This is desirable because firing against the mass increases the time required for incineration, causes smoke (especially at the beginning of an operation) and brings about packing and case hardening of wet masses of certain types of combustible materials, with resultant production of large and relatively incombustible aggregates.

Thus my invention contemplates the improvement in the burning of garbage and similar material which is markedly heterogeneous both as to size and composition which comprises tumbling the material downward through a series of superposed combustion zones through flames projected across each of the zones, and retaining the material in each of the zones for a period at a level below the projected flame of that zone before tumbling it through the projected flame or the next lower zone.

The several combustion chambers may be fired from adjacent fire boxes, but preferably they are heated by burners which project a mixture of air and fuel, say producer gas, natural gas, fuel oil or pulverized coal into the chamber at a substantial distance above the hearth to produce a stream of flaming gases of combustion.

Gaseous products of combustion may be removed from the furnace in several ways. In a simple form of the apparatus of the invention an exit flue is connected to the uppermost combustion chamber. Gases from lower chambers find their way into the uppermost chamber through gaps between or in the hearth sections. For better control of combustion on the individual hearths, each may be provided with a dampered exit flue, with all of these exit flues discharging into a common header.

In many cases, it is desirable to pass the flue gases through an additional combustion chamber, into which no garbage is dumped. This additional chamber is provided with a separate heating means, say a fuel oil burner, which maintains the chamber at a temperature of at least 1000 F. At this temperature volatile substances, smoke, fume, etc., driven off the garbage are burned completely, thus removing odors and visible smoke and giving a clear stack discharge.

The hearths are disposed inside an upright hollow column. They may be of any area, depending upon required furnace capacity. The hearth may be of any shape, say round, rectangular, or triangular, although for simplicity of construction a hearth that is of rectangular plan is preferred. There should be at least two combustion chambers, each separately fired, but in most installations a larger number of chambers and superposed hearths are desirable.

Each hearth is composed of a plurality of sections or plates, which substantially abut each other when the hearth is in the uncollapsed condition. Each section is hinged at one end, so that it will swing downwardly when released. Means are provided for swinging each hearth section up into its original position after it has swung down and discharged its load. Preferably each hearth section is hinged to the wall of the column, against which it swings when released. This facilitates repair and simplifies construction and operation.

The hearth sections may be provided with internal conduits through which cooling gases or liquids are passed. In a preferred form of hearth section, its internal conduits are fed with air under pressure, and this air is discharged through perforations in the hearth section which point either upwardly, so as to discharge a blanket of hot secondary air into the pile of combustible on the section, or downwardly to supply hot secondary air for combustion in the chamber immediately below.

Secondary air, i. e. air in addition to that admitted with the fuel at the burners, may be introduced in a number of other ways. For example, air under pressure may be heated by stack gases through the medium of a heat exchanger and fed into one or more combustion chambers directly.

In certain instances it is advantageous to bypass gas from one combustion chamber to another chamber. This is accomplished by means of a manifold flue having dampered branches into each combustion chamber.

These and other aspects of my invention will be understood thoroughly in the light of the following detailed description, taken in conjunction with the accompanying drawings in which:

Fig. 1 is an end elevation, partly in section, of one form of the apparatus of the invention;

Fig. 2 is a side elevation, partly in section, of the apparatus of Fig. 1;

Fig. 3 is a fragmentary top view, partly in section of the apparatus of Fig. 1;

Fig. 4 is an enlarged plan view of a hearth section of the apparatus of Fig. 1;

Fig. 5 is a sectional elevation through the hearth section of Fig. 4, taken along the line 55;

Fig. 6 is a sectional elevation through a modification of the hearth section of Figs. 4 and 5;

Fig. 7 is a diagram illustrating hearth section arrangement in a furnace of the invention of elongated rectangular plan;

Fig. 8 is a diagram illustrating hearth section arrangement in a furnace of the invention built in circular plan;

Fig. 9 is an end elevation, partly in section of a simplified form of the apparatus of the invention;

Fig. 10 is a side elevation of the apparatus of Fig. 9;

Fig. ll is a plan of a hearth of the apparatus of Figs. 9 and 10; and

Fig. 12 is an end elevation of the hearth of Fig. 11.

The apparatus of Figs. 1 to 5 is enclosed in an upright Y masonry column 10 of square cross section (see Fig. 3). The apparatus has multiple superposed horizontal sectional hearths 11 of which four are shown. These substantially fill and block the column at the several levels.

Between the hearths are three combustion chambers 12,

about as deep as the hearths are wide. Above the first or uppermost hearth there is an additional chamber or bin 13 about the depth of a combustion chamber and into which material to be incinerated (say garbage) is dumped, either in batches from a truck, or continuously from a belt conveyor (not shown). The top of the bin 13 opens through an operating floor 14.

Below the lowest hearth there is a chamber or ash pit 15 from which unburned material may be withdrawn by any conventional means. Thus the pit can be constructed with a hopper bottom (not shown) to facilitate withdrawal of ash into cars, etc.

Each hearth is composed of four approximately square sections 16. One pair of hearth sections is hinged adjacent one side wall and the other pair of hearth sections is hinged adjacent the other side wall. For each pair of hearth sections two ends bearings 17, 18 and a double central bearing 19 are provided. Short hollow shafts 20, 21 formed integrally with the respective sections, project through the end bearings respectively, and are connected at the inside to air passages in the respective hearth sections. The common or central bearing 19 is disposed at the middle of the side wall. The two hearth sections have solid integrally-formed stub shafts 22, 23 journaled in the central bearing.

Operating levers 24 are fastened rigidly to each hearth section. These operating levers project through V-shaped vertical slots 25 in the sides of the column. The outside end of the lever is connected by a hinge to a piston rod 26 of a cylinder 27, the lower end of which is fastened by a hinge 28 to the outside wall of the furnace. Thus the operating lever, the piston and the cylinder lie in the same vertical plane. When the hearth is uncollapsed and stands in the horizontal position (see Fig. l), the pistons are retracted into the cylinders and the operating lever is drawn down so that it makes an angle of about 45 with the horizontal. When fluid, say compressed air, is admitted into the cylinder to push the piston and the outside end of the operating lever up, the hearth section swings downward on its hinge to lie in a substantially vertical plane against the adjacent side wall of the column. When this happens, the operating lever is swung approximately 90 upward in its slot.

The piston-cylinder combination is of the conventional double acting type, so that fluid may be admitted on either side of the piston and force it up or down. As soon as a hearth section is dumped it is returned to horizontal position, preferably by conventional automatic valve control means, not shown.

The individual hearth sections are about half as long tween combustion chambers.

as the combustion chambers are deep, so that they can swing free to the side walls without entrapping material held on the next lower hearth.

Each combustion chamber is provided with two bumers 30, 31 (see Fig. 2). These are located on the end walls and throw flames in a relatively horizontal direction across the combustion chamber from end to end, i. e. in a direction substantially parallel to the hinge axes of the hearth sections. The burners are mounted about midway between hearths and on the vertical center line of the end walls, so that when the hearth sections are swung downward they themselves do not pass through the axes of the hot blasts from the burners.

The apparatus is provided with a stack 34 disposed to one side of the furnace column. Exit flues 35 project from the ends of each of the combustion chambers just below the tops. Each exit flue is provided with a damper 36 and all discharge into a vertical header flue 37 which in turn discharges into the bottom of a deodorizing charrber 39, having a baflle 40. The deodorizing cham ber discharges into the stack through a stub flue 41. A burner 42 is mounted on the end of the deodorizing chamber nearest the furnace column and projects a flame length wise through the deodorizing chamber above the battle.

A second vertical header flue 44 is mounted adjacent the end wall of the furnace column opposite that of thc first header flue 37. It is provided with branch flucs 45, each of which contains a damper 46. These branch fines communicate with the respective combustion chambers in the upper portions thereof.

Secondary air for combustion is admitted into the furnace through the hearth sections which are fed by a pipe system 50. This comprises vertical manifold pipes 51, 52 disposed adjacent the outsides of the end walls, each manifold being provided with valved branch pipes 53 which discharge air respectively into the hearth sections through swivel joints 54 coupled to the hollow shafts on which the sections swing. Prior to introduction into the hearth sections, the secondary air may be preheated by passing it through a heat exchanger 55 disposed in the stack so that waste heat of the stack gases is utilized. The secondary air is forced through the heat exchanger from an inlet pipe 56 to an outlet pipe 57 and thence to the two manifolds 51, 52.

The hearth sections may be uncooled plates or grates, but it is preferable to air-cool the hearth sections and to utilize the air thus preheated as secondary air for drying or combustion. Thus, the hearth sections may be constructed as shown in Figs. 4 and 5. Air under pressure is admitted into the interior of the hearth sections through the hollow shafts 20, 21 which are connected to the coaxial pipes 53 through the swivels 54. This air passes through an integrally formed header 60 on the axis of the hinge and out through hollow branches 61, 62, 63, 64, formed integrally with the header and With the webs or plate portions of the hearth section. The air may be expelled from the branches, as shown in Fig. 5, through holes 66 directed upward. If desired, holes 67 may be disposed in the lower wall of the branches, as shown in Fig. 6, so as to discharge preheated secondary air downward.

If it is desired to pass gas upwardly directly from one combustion chamber to another, the hearth sections may be separated from each other by small gaps 68 (see Fig. 3). These provide passages directly be- In some cases the gaps between sections or passages through sections made in grate form are adequate. In such cases it is unnecessary to employ the manifold outlet flue 37 (shown in Fig. 2), only the top combustion chamber being connected by flue to the deodorizing chamber (see Figs. 9 and 10).

The operation of the apparatus of Figs. 1 to 5 is as follows:

Garbage or other material to be incinerated is dumped continuously or in batches into the receiving bin at the top of the column. Preheated air passes up through the hearth sections into the bed of material retained in the bin and accomplishes some drying action. Periodically the hearth sections are dropped, to discharge the material retained on them into the next lower chamber. If desired, all of the sections of a given hearth may be dropped simultaneously, but it is preferable to drop the hearth sections individually, in a cycle one after the other, and at predetermined intervals, so that the batches dropped at any given time are relatively small. When a hearth section is dropped, the material retained on it tumbles to the next lower hearth through the hot gases of combustion from the burners.

The operation should be so conducted that the bed of material retained on any hearth does not reach above the burners in the combustion chamber immediately above that hearth. This prevents firing against the mass and greatly increases combustion efficiency.

After sufiicient combustion has occurred in any of the combustion chambers, its bottom hearth is collapsed either in total or section by section, to tumble the contents onto the next lower hearth, through the hot blasts from the burners, this operation being continued and so controlled that the material, say garbage,

is burned completely before it is dropped from the lowermost hearth into the ash pit.

The dropped hearth sections do not extend substantially below the burner in the next lower combustion chamber. if the furnace load is controlled so that the piles on each hearth are disposed below the respective burners there is no chance for material to be pressed and caked against the walls by the hearth sections as they drop.

The dampers 36 in the outlet fiues leading to the header 37 are adjusted so that proper draft is produced in each combustion chamber. However, even under extremely good conditions of combustion, some material is volatilized, evaporated, or formed into smoke or fume particles, and consequently it is desirable to subject all the gases of combustion from the furnace to further heat in the deodorizing chamber, this being maintained at a temperature of 1000 F. or more so that the combustion of fumes, smoke, vapor, etc. is completed to produce a substantially colorless and relatively odorless stack gas.

Combustion and thermal efliciency are both improved if the secondary air is preheated. Thus the secondary air for combustion may go through the heat exchanger in the stack and thence through the piping system to be discharged either upwardly or downwardly through the hearth sections.

If there is a tendency for material to stick to the hearth sections when they are dropped, scraping means may be provided. A simple type of automatic scraping means is shown in the receiving bin of Fig. 1.

parallel to the hinge of the section and close to the wall when the hearth section is horizontal. It is fastened to the end of long bars 74 which are hinged about a pin or rod 75 in the bin on the center line between hearth sections, so that the axis of rotation of the bars is parallel to and substantially above the hearth hinge. When the hearth section is dropped, the blade is unsupported and tends to swing inwardly so that it drags along the surface of the dropping hearth section for a substantial distance. A stop 76 is so positioned on the bin that the bar strikes it before it has swung into a vertical position. Preferably the stop is so placed that the movement of the blade is interrupted at the point where it loses contact with the downwardly swinging hearth section.

The scraper blade, even though it was allowed to swing to the middle of the furnace, would not scrape the entire surface of the hearth section, but in many instances it is not necessary to scrape the unhinged end It comprises a scraper blade 73 lying on a hearth section 6 of a hearth section, in which case the apparatus just described is adequate. When the hearth section is raised it makes contact with the scraper blade and returns it to its original position adjacent the hinge of the hearth section.

If it is desired to scrape the unhinged end of a hearth section automatically, this may be accomplished with a second scraper blade 77 which is disposed parallel and adjacent to the unhinged end of the hearth section. It is swung from bars or rods 78 that extend up and out to a hinge pin or rod 79 adjacent the column wall above the hearth hinge. As the hearth section swings down, the second scraper blade also swings down in contact with the hearth section and scrapes. Eventually it loses contact with the hearth section, but not until it has scraped that portion which the first blade misses. The second scraper blade comes to rest when the rods upon which it is swung come in contact with the first scraper blade, and is automatically returned to its original position by the hearth section when it is swung upward.

Each hearth section may be provided with either or both of the automatic scraping mechanisms described.

The apparatus illustrated in Figs. 1 and 2 is approximately 4 feet square inside the column. Thus the hearth sections are approximately 2 feet square. For greater tonnages the furnace may be modified by increasing its plan section or increasing the number of hearths, or both.

As indicated at the outset, it is desirable that the column be rectangular in plan. Fig. 7 is a diagram showing a hearth arrangement for a furnace 70 that is rectangular in plan and provided with eight square hearth sections 71, four hinged on each side, the hearth sections being provided with individual means, for swinging them individually on their hinges.

In a round column, the arrangement shown in Fig. 8 may be employed. The hearth section 72 are three in number and pie-shaped each including 120 of the circle and being hinged to the wall, as shown.

It is not essential that the hearth sections be hinged to the column walls, and they may be hinged from a rod or pipe passing through the interior of the column. This, however, is not so desirable because maintenance and repair are simpler if the hinges are adjacent the walls and thus relatively accessible.

If slurries, sludges, or liquids are treated in the furnace the hearth sections may be in the form of hinged pans 81 (see Fig. 6) with raised edges or lips so that they will retain pools when disposed in the horizontal position but will drain completely when dropped.

The apparatus of Figs. 9 to 12 is constructed according to the same basic principles as that already described, but varies in plan and has five combustion chambers 83 separated by superposed sectional collapsible hearths 84, which form the tops and bottoms of the chambers. Above the uppermost hearth there is a receiving bin 85 and below the lowermost hearth an ash pit 86. An exit flue 87 projects from one side of the top combustion chamber and extends upward to open into the bottom of a deodorizing chamber 88 disposed to one side of the column and slightly above the uppermost hearth. The deodorizing chamber in turn discharges into a stack 89.

The top combustion chamber is substantially deeper than the other chambers, to accommodate a larger hearth load and to permit hearth sections to be dropped without blocking the exit flue.

Hearth construction is best shown in Figs. 11 and 12. Each hearth is composed of four substantially square sections 90, individually hinged in pairs adjacent opposite side walls of the column. Each hearth section is an integral casting of heat resisting metal. On its inside end it has a small hollow stub shaft 91 which turns in a double bearing 92. Air under pressure is fed into this double bearing from a pipe 93 at the outside of the column and finds its way through the respective hollow stub shafts of the pair of hearth sections into manifold conduits 94 inside the respective sections. These manifolds extend along the hinge axes of the sections and feed integrally formed branch conduits 95, 96 which extend in each section from the manifold at right angles. Each branch conduit has a series of perforations 97 along its top to dicharge pre-heated air into the chamber above the hearth. A web or grate 98 with slits 99 extends between and on the outsides of the branch conduits. An operating shaft lt'lil on the outside of each hearth section and coaxial with the inner stub shaft projects through a bearing 101 in the end wall of the furnace column. attached to and preferably formed integrally with the hearth section. A crank arm 102 is fastened rigidly to its outside end. The crank. is hinged by a pin connection 103 to the end of a rod 104 of a piston pro jection from one end of a horizontally disposed cylinder 1 105. The opposite end of the cylinder is hinged by a pin connection 106 to a tie member 167 which extends horizontally along the outside of the masonry column at the hearth level. The piston-cylinder combination is double acting, i. c. air or other fluid may be forced into the cylinder by means (not shown) on either side of the piston and thus cause the piston rod to be forced either into or out of the cylinder. Alternatively, the combination may be spring-loaded, so that the hearth sections are held horizontally except when fluid under 1;.

pressure is admitted to the cylinder. When the piston rod is retracted the hearth section is held in a horizontal position; when the piston rod is extended its hearth section is swung down through an arc of approximately 90 into a substantially vertical position.

Returning now to Figs. 9 and l0, it will be seen that each combustion chamber is provided with two burners 108, 109 mounted on the end walls on opposite sides of the center line. The burners project flames through their respective ports lit), lll horizontally through the i combustion chambers at a substantial distance above the hearths. The burner pairs are staggered so that they have separate flame paths.

Cleanout doors 112 are provided on the side walls opposite the flue for each combustion chamber.

The deodorizing chamber is provided with a separate burner 113 which projects a flame through a port into the chamber, as in the case of the apparatus of Figs. 1 to 5 and for the same purpose.

In the operation of the apparatus of Figs. 9 to l2,

garbage is dumped intermittently or continuously into the receiving bin, the bottom of which is formed by the top hearth. Each hearth section is controlled individually, and they are lowered and raised one after another in a cycle, so that each time approximately one quarter of the contents of the receiving bin is dumped into the first or top combustion chamber. Each batch thus dumped tumbles down through the flames in the combustion chamber to land on the second hearth. When combustion has progressed far enough, the sections of the second hearth are lowered and raised one after the other to tumble their contents through the flames of the second combustion chamber onto the third hearth, and so on until the last of the garbage is burned on the bottom or sixth hearth. As soon as a hearth section is dumped and returned it is re-filled from above, so that the operation is substantially continuous.

The gaseous products of combustion from each hearth find their way upward in the furnace column through the slits in the hearth sections and through the narrow gaps H4 between the sections of a hearth (see Fig. 11). Thus all the gases of combustion are finally withdrawn from the furnace through the exit flue from the first or top combustion chamber to be subjected to a further burning at high temperature in the deodorizing chamber.

The shaft is rigidly The flame axes and the hinge axes of hearth sections are substantially parallel and are sufficiently removed from each other that the flames do not impinge directly on the hearth section as these are raised and lowered. However, this construction is such that the material sliding off the hearth section is tumbled directly through the burner blasts. As in the case of the apparatus of Figs. 1 to 5, the loads on the various hearths should be kept below burner level to avoid firing against the mass of the loads, and thus avoid the difficulties due to such firing. However, the apparatus of Figs. 9 to 12, like that of Figs. 1 to 5, will operate with heavy loads on the hearthsalthough not so well.

The apparatus of my invention is simple, rugged and has an exceedingly high through-put and thermal efliciency as compared with furnaces heretofore available for the incineration of garbage and the like.

I claim:

1. In a furnace, the combination which comprises an upright hollow column, a plurality of hearths disposed one above the other in the column and spaced from each other to provide a plurality of combustion chambers in the column between hearths, firing means disposed at each of the combustion chambers to throw flames across the hearths, each hearth being composed of a plurality of sections with each section hinge-supported at one end, and the hearth sections being composed of hollow multi-perforated members joined together by webs, means for releasing each hearth section so that it hangs from its hinged end, means for swinging each hearth section upward to hearth position, and means for introducing compressed air into the combustion chambers through the hollow members of the hearth sections.

2. Apparatus in accordance with claim 1 in which the perforations in the hollow members of the hearth sections are directed downward and supply air to the chambcr underlying the hearth section.

3. Apparatus in accordance with claim 1 in which the perforations in the hearth sections are directed upward to discharge air into a bed of material on top of the hearth sections.

4. In a furnace, the combination which comprises an upright hollow column, a plurality of hearths disposed one above the other in the column and spaced from each other to provide a plurality of combustion chambers in the column between hearths, firing means disposed at each of the combustion chambers to throw flames across the hearths, each hearth being composed of a plurality of sections each provided with internal conduits opening through perforations into a combustion chamber, with each section hinge-supported at one end, adjacent the column wall, means for releasing each hearth section so that it hangs from its hinged end, means for swinging each hearth section upward to hearth position, a bearing disposed adjacent the column wall with two hearth sections hinged in it, and means for supplying air under pressure to the internal conduits of both of these hearth sections through the bearing.

5. In a furnace, the combination which comprises an upright hollow column, a plurality of hearths disposed one above the other in the column and spaced from each other to provide a plurality of combustion chambers in the column between hearths, firing means disposed at each of the combustion chambers to throw flames across the hearths, each hearth being composed of a plurality of sections with each section hinge-sup ported at one end, means for lowering each hearth section from its hinged end, means for swinging each hearth rcction upward to hearth position, scraping means disposed above at least one of the hearth sections and resting on that section when it is in hearth position, and an arm fastened to and slanting upward from the scraping means and hinged at its upper end, so that the scraping means moves across the hearth section as the latter is raised and lowered.

References Cited in the file of this patent UNITED STATES PATENTS 10 Leask June 10, 1913 Nieberding Aug. 7, 1917 Breitwieser Aug. 19, 1930 Langford Sept. 30, 1930 Parker Sept. 13, 1932 Van Denburg Mar. 26, 1935 Hiler Jan. 31, 1939 Lewers Mar. 14, 1939 

